How are Ferritin Eisenmangel and Müdigkeit related?

Ferritin is the body's primary iron storage protein. Low ferritin indicates iron deficiency, which reduces hemoglobin production and leads to anemia – a well-known cause of fatigue. However, iron deficiency can cause fatigue even without anemia by impairing mitochondrial energy production and neurotransmitter synthesis (e.g., dopamine). The evidence is strong: Cochrane reviews and multiple clinical trials show that iron supplementation significantly reduces fatigue in iron-deficient individuals. Caveat: Ferritin is an acute-phase reactant; inflammation, infection, or chronic disease can falsely elevate ferritin levels, masking a true deficiency. Therefore, always measure CRP alongside ferritin. For persistent fatigue with suspected iron deficiency, a medical workup including complete blood count, ferritin, transferrin saturation, and CRP is recommended before starting iron supplements.